Alexa works, but stops responding after a while (about 2 hours)

[dkoce]

Hello,
I managed to setup a MM with MMM-awesome-alexa and everything worked fine at first. But after some time (it differs, though something between 1-3 hours) Alexa stops responding. The MM is still working properly.
A restart of MM with "pm2 restart mm" does not change anything - after MM restarting, Alexa is still not responding.
With a complete reboot of the RasPi, everything works fine again. Alexa is responding.
I cannot find any suspicious log entry that would give me some hint.

I´m using a RasPi 3B, latest image from https://magicmirror.builders/

Did someone experience the same behavior? And do someone have a solution other then restarting the RasPi every hour?
Thanks for your help!
Best regards,
Dieter